An automated manual transmission (AMT) or a double clutch transmission (DCT) has a clutch capable of automatically transmitting power by an actuator and when the clutch is used as a dry type, since a touch point which is an actuation start point of the clutch is changed by a change in temperature of the clutch or abrasion, appropriate adjustment of the touch point is required to maintain stable operability of the clutch.
FIG. 1 is a graph showing characteristics of clutch torque in respect to a stroke of a clutch actuator, in which when the stroke increases and reaches the touch point, the clutch torque starts to increase at last and then, when a state of the clutch is normal, maximum clutch torque designed to be larger than maximum engine torque which an engine may transfer in a maximum stroke may be transferred, but when the touch point moves due to the change in temperature of the clutch or the abrasion, the maximum engine torque may not be completely transferred even in the maximum stroke.
Like this, the touch point is a primary factor that continuously stably maintains an appropriate control relationship between the clutch actuator and the clutch and FIG. 2 is a diagram for describing a method for detecting and setting a touch point of a clutch in the related art, in which the method is performed while stopping or when a gear box is neutral directly after engine cranking.
That is, in the related art, the position of the clutch actuator is determined as the touch point at the time (B) when the clutch starts to rotate by actuating the clutch actuator toward a direction in which the clutch is joined from a position in which the clutch is not joined (A) and the position is adjusted to a new touch point (C) and thereafter, the clutch actuator is actuated based on the newly set touch point.
To this end, in the related art, since the touch point of the clutch is detected with respect to a change of angular acceleration of an input shaft, the touch point of the clutch may be mis-detected depending on a variation of angular acceleration of the input shaft.